This study concerns a prospective, longitudinal investigation of children with schizophrenic mothers, schizophrenic fathers, and two schizophrenic parents. As groups, these children are known to be at high risk for the eventual manifestation of schizophrenia. In prospective studies antecedent conditions and the pathogenic process relating to the development of the disorder may be investigated prior to overt onset of the illness. Long-term goals of this research are directed toward analyses of biological-environmental interactions and toward instrumentation of preventive intervention programs based on a more firm understanding of etiological factors and the premorbid state. Emphasis is placed on measures relating to attentional and information processing deficiencies and on neurophysiological dysfunction. In the longitudinal follow-up, the current clinical status of the subjects is being examined as a possible indicator of later psychiatric outcome and an interim validator of the predictive value of specific deviancies noted in early assessments. Attention will be given to factors that differentiate vulnerable and resistant children within the high-risk groups. A sample consisting of 80 children with one or two schizophrenic parents, 25 children of parents with other psychiatric disorders, and 100 children of normal parents has been followed since 1971; the age range of these children upon initial examination was 7-12 years. This sample has been re-examined twice and will receive a fourth examination during the renewal period. Collection of a second sample of approximately 150 7-12 year old high-risk and comparison children is nearing completion; this replicate sample will be examined for a second time during the renewal period. All subjects are followed by telephone contacts at 3-6 month intervals between examinations.